Tube reducing machine



1967 A. F. TREMBLAY 3,357,223

TUBE REDUCING MACHINE Filed May 28, 1965 6 Sheets-Sheet 1 INVENTOR: ALBERT f. TREMBLAY Dec. 12, 1967 A. F. TREMBLAY 3,357,223

TUBE REDUCING MACHINE Filed May 28, 1965 6 Sheets-Sheet 2 Z6 /z7 K 2? INVENTOR: ALBERT F TREMBLAY AT T75.

Dec. 1957 A. F. TREMBLAY 3,357,223

TUBE REDUCING MACHINE Filed May 28, 1965 6 Sheets-Sheet 5 INVENTOR. 14L351; TI TEEMBLAY.

ATTl s- 1967 A. F. TREMBLAY 3,357,223

TUBE REDUCING MACHINE Filed May 28, 1965 6 Sheets-Shed 1* gum mmm ummmmm- L 'llll. I h] INVENTOR' ALBERTf TREMBLAZ lili- 5 Q Dec. 12, 1967 A. F; TIQQEMBLAY 3,357,223

TUBE REDUCING MACHINE Filed May 28, 1965 6 sheets'sheet 5 5 35 3 25 2o :5 lo 5 f 5 o 0 Z1 3 3 fio T I 1 1 *r I I I I Q i I l 1 I w I u if 7 INVENTOR' .ATTYS.

A. F. TREMBLAY TUBE REDUCING MACHINE Dec. 12, 1967 6 heets-Sheet 6 Filed May 28, 1965 A/Pa LEA/6n) I 4/?c 461/6774 I TITj 5 FEED-- INVENTOR:

ALBERTF TREMBLAK.

.AT Tys.

United States Patent 3,357,223 TUBE REDUCENG MAHINE Albert F. Tremblay, Toledo, Ohio, assignor to Kent- Owens Machine Company, Toledo, Ohio, a corporation of Ohio Filed May 28, 1965, Ser. No. 459,661 4 Claims. (Cl. 72189) ABSTRAQT OF THE DHSCLOSURE A tube reducing machine having an improved drive arrangement and an improved die holder arrangement is provided. The machine has a unique drive in which arms of the die holders are connected by common linkages to a single crankshaft located to one side of the path of the tubing being formed. The links are driven in opposite directions to enable a balance of forces on the drive system. The dies of the machine are held in the die holders by an arrangement which enables the dies to be accurately positioned and adjusted for wear.

This invention relates to an improved tube reducing machine.

A tube reducing machine of the type under consideration transforms a heavy tube or tubular billet into a tube of smaller diameter and of lesser wall thickness. This is accomplished by a pair of mating die rolls which engage and roll over the tube while under extreme pressure. Tubes produced in this manner are of very high quality, being of accurate dimensions and high strength. The process also is particularly useful in making tubes of certain alloys and metals such as titanium and zirconium.

Heretofore, such tubes have been made by means of a pair of mating rolls which engage and roll over the tube in forward and reverse directions through arcs of approximately 180. The upper and lower rolls were contained in a reciprocating frame or saddle supported for reciprocation in a path parallel to the axis of the tube being rolled. The saddle was connected to a continuouslyrotating crank through suitable connecting rods with the saddle moving through one complete forward and reverse cycle for each complete revolution of the crank. At one end of one stroke, the tube was moved axially forwardly a predetermined amount and at the end of the opposite stroke, the tube was rotated a predetermined amount. The stroke after the axial feeding of the tube served to cold form and reduce the tube while the stroke after the rotation of the tube primarily served to smooth or iron the tube.

The saddle supporting the tubes was subjected to considerable pressure during the cold forming operation through the forces acting on the rolls and the saddle had to be extremely massive. Consequently, the power required to reciprocate the saddle and the rolls was substantial. Further, the large masses and inertia involved during reciprocation severely limited the number of strokes per unit of time which could be achieved. This, in turn, limited the production rate of the reduced tube.

Because of the large are through which the die rolls reciprocated, the die inserts held by the rolls frequently were loosened due to the large variation in direction from which pressure was applied, resulting in relatively frequent die breakage due to the constant hammering effect of the loose die inserts during each pass over the tube. The rolls heretofore employed also were of relatively small diameter, resulting in substantial skidding or sliding between the rolls and the tube. The rolls were normally coordinated through suitable gearing which usually included a pinion gear meshing with a rack located at the otuside diameter of each roll, at the center line of the tube. Consequently, only true rolling was produced at the pitch diameter of the pinion gear with sliding or skidding contact occurring between the roll and the tube beyond the pitch line. This resulted in rapid die wear and also produced longitudinal skid marks on the surface of the tube. The skidding also resulted in considerable heat with consequent power loss.

The present invention relates to an improved tube reducing machine having many advantages over those heretofore known. The new tube reducingmachine incorporates a pair of dies constituting die blocks and die inserts having diameters many times the diameters of the die rolls heretofore used. The new die blocks are mounted in a stationary frame rather than a reciprocating one with only the die blocks being reciprocated by a crank drive rather than the entire saddle in which the die blocks are mounted being reciprocated, as heretofore. Consequently, the energy required to move the heavy components through reciprocating motions is substantially reduced and the rate at which the die blocks are reciprocated can be increased. Further, whereas with the prior apparatus, a ratio of saddle movement to crank movement of only 1:1 could be attained, with the new apparatus a much higher ratio, approaching 2:1 can be achieved of the travel of the die blocks to the length of the crank stroke. This has enabled further increase in the reciprocation rate of the die blocks without necessarily increasing the speed of the crank.

With large diameters, the die blocks can achieve a stroke length equal to that of the die rolls heretofore known by movement through an arc of relatively few degrees. Consequently, the forces applied through the die inserts are applied generally in only one direction with the result that loosening of the die inserts and consequential breakage is infrequent. The large diameter of the die blocks results in substantially less slipping or skidding between the die block inserts and the tube, resulting in less wear of the die inserts and smoother finishes on the reduced tubes. Also, the energy lost in the form of heat due to slipping is substantially reduced, as is the power requirement.

It is, therefore, a principal object of the invention to provide an improved tube reducing machine having many advantages over those heretofore known.

Another object of the invention is to provide an improved tube reducing machine in which the supporting frame for the die blocks and die inserts is stationary.

A further object of the invention is to provide a tube reducing machine having die blmks and die inserts of diameters many times larger than those heretofore known.

Yet another object of the invention is to provide a tube reducing machine in which die inserts are less subject to breakage than heretofore.

Yet a further object of the invention is to provide a tube reducing machine capable of higher production rates.

Still another object of the invention is to provide a tube reducing machine capable of more strokes per unit of time and with less energy required.

Still a further object of the invention is to provide an improved tube reducing machine having a higher ratio of stroke length to crank length.

Many other objects and advantages of the invention will be apparent from the following detailed description of a preferred embodiment thereof, reference being made to the accompanying drawings, to which:

FIG. 1 is a fragmentary side view in elevation of a tube reducing machine according to the invention, with parts broken away, and of apparatus for supporting, feeding, and turning a tube being reduced;

FIG. 2 is a fragmentary plan view of the apparatus of FIG. 1;

FIG. 3 is a fragmentary view in vertical cross section, on a greatly enlarged scale, taken along the line 3-3 of FIG. 1;

FIG. 4 is a side view in elevation of the tube reducing machine of FIGS. 1 and 3, on a slightly smaller scale than FIG. 3, with parts broken away and with parts in cross section;

FIG. 5 is a right side view of the machine of FIG. 4, with certain parts removed;

FIG. 6 is an enlarged, fragmentary view in vertical cross section, taken along the line 6--6 of FIG. 3;

FIG. 7 is a right end view of the components of FIG. 6;

FIG. 8 is a diagrammatic view showing a comparison of a large diameter die according to the invention and a small diameter conventional die roll;

FIG. 9 is a diagrammatic view showing various lengths and relationships between several components of the machine embodying the invention; and

FIG. 10 is a schematic view of a slightly modified tube reducing machine embodying the invention.

Referring to FIGS. 1 and 2, a tube reducing machine 12 embodying the invention is shown with the usual means for feeding and turning a tubular billet in coordination with the operation of the tube reducing machine 12. This is accomplished through an indexing mechanism 13 which coordinates feeding and turning mechanism 14 with operation of the machine 12. The mechanism 14, through a gear connection 15, is synchronized with a turning mechanism 16 so that the tube is turned by mechanism at both ends of the machine but is fed by mechanism only at one end. The mechanisms 14 and 16 are known in the art and will not be discussed in detail. The billet 18 usually is from about 8 to 16 feet long prior to being reduced. In a typical example, the billet 18 has a 3 inch diameter initially which is reduced to 2 inches, along with a reduction in the thickness of the wall of the tube from /2 to A inch by the time it emerges from the machine 12. The tube can be fed axially about inch each time the die components of the machine 12 reach the end of their forward stroke, and the tube can be rotated, typically 40, each time the die components reach the end of their rearward stroke. Depending upon the particular operation, the feed of the tube can vary from about inch to about 1 inch while the rotation can vary from approximately 20 to 60. A mandrel is employed within the tube in the conventional manner to control inside diameter.

Referring more particularly to FIGS. 3-5, the tube reducing machine 12 includes a stationary frame 20, an upper die assembly 22, and a lower die assembly 24. The stationary frame 20 includes a drive housing or base 26, side frame members 28 and 30, upper corner posts 32, and an upper frame member 34. The overall upper die assembly 22 includes an upper stationary axle 36 supported by the upper frame member 34 through ears 38 and 40 and caps 42 and 44. Because the axle 36 is urged upwardly during a tube reducing operation, relatively little stress is placed on the ear caps 42 and 44. Large roller bearings 46 and 48 are rotatably supported on spaced cylindrical portions 50 and 52 of the axle 36.

A connecting link 54 has upwardly-extending yokes 56 and 58 at the upper end rotatably received on the roller bearings 46 and 48 and provided with suitable covers 60 and 62 extending around the bearings 46 and 48. It is not necessary for the yokes 56 and 58 to extend completely around the bearings 46 and 48 since most force on the link 54 is in an upward direction. However, the covers 68 and 62 serve to retain the yokes 56 and 58 on the bearings 46 and 48 at the ends of the strokes, when no force is applied through the dies. The link 54 further includes a pair of outboard cylindrical portions 64 and 66 at the lower end carrying additional roller bearings 68 and 78.

An upper die holder or die block 72 is located below the link 54 and has upper yokes 74 and 75 received around an rotatably supported by the roller bearings 68 and 70. Outer covers 76 and 77 also retain the holder 72 relative to the bearings 68 and 78 during end portions of the strokes of the dies. The die holder 72 extends through an included angle of about 30 and carries at one side a gear sector 78 meshing with a gear rack 80 carried by the frame member 30 in order to assure a rolling type of motion of the holder 72. Centrally, the holder 72 has a longitudinal groove 82 in which is carried an upper die or die insert 84. The lower surface of the die insert 84 is substantially flush with the corresponding surface of the holder 72 but the die insert 84 extends through an angle of only approximately 23 compared to about 32 for the die holder 72. The die insert 84 has a die surface 86 of substantially semi-circular transverse cross section but having a radius at the forward end (left end as shown in FIGS. 4 and 6) exceeding that at the rearward or right end so that the cross-sectional area formed by the die surface 86 diminishes from the left or forward end to the right or rearward end. The radius of the die surface 86 at the forward end of the die insert 84 is substantially equal to the radius of the tube or billet to be cold formed. The radius at the rearward end of the die insert is substantially equal to the final desired radius of the tube, actually being slightly smaller to allow for springback" of the metal.

The die insert 84 is accurately located in the die holder groove 82 by an upper shim 88, and by a locating bar or stop 90 and a wedge 92 held by an adjusting bolt 94 against a backup bar 96 at the opposite end. In addition, the die insert 84 is held against one side of the groove 82 by a side wedge 98 tightened and held by an adjusting screw 100. The wedges 92 and 98 thereby assure that the die insert 84 will be accurately located with respect to one side of the groove 82 and the stop 90.

The lower die assembly 24 includes a lower die or die insert 102 which includes a die surface 104 similar to the surface 86. The die insert 102 is held in a die block or holder 106. The die holder 106 is substantially identical to the holder 72 and also has a gear sector 188 meshing with the gear rack 110 affixed to the frame member 28. A pair of downwardly-extending yokes 112 and 113 are rotatably supported by a third pair of roller bearings 114 and 115 with covers 116 and 117 extending therearound. The bearings are mounted on cylindrical extensions 118 and 120 of a lower link 122. The link 122 has downwardlyextending end portions or yokes 124 and 125 received on a fourth pair of roller bearings 126 and 127 with covers 128 and 129 extending therearound. The bearings are mounted on cylindrical end portions 130 and 132 of a lower axle 134.

As shown in FIG. 4, the axle 134 is supported on the top of the base or housing 26 by a wedge 136 which can be adjusted by a bolt 138 and nuts 140. The wedge 136 is used to pre-load the die assemblies by placing a predetermined pressure between the die holders '72 and 106 and the die inserts 84 and 102. The pre-load force required to prevent separation of the die inserts can be substantial. For example, for a 3 /2 inch diameter tube with a /2 inch wall thickness, which is reduced to an outside diameter of 2 /2 inches with a inch wall thickness, this force can amount to 300,000 pounds or more, depending on the type of material being processed.

The dies 84 and 102 in this instance are much larger in diameter than the die rolls heretofore used in tube reducing machines. For example, with conventional dies, the overall diameter of the die roll for a 3 /2 inch billet or tube to be reduced to 2 /2 inches is 17 inches or approximately five times the diameter of the tube being rolled. With the same 3 /2 inch tube, the dies 84 and 102 have a diameter of 120 inches or a die diameter to tube diameter ratio of approximately 35:1. As another example of the contrast in diameters, with a conventional die roll, for reducing a 2 /2 inch tube to 1% inches, the

die roll diameter is 13 inches, whereas with the dies 84 and 102 under the same circumstances, the diameter again is 120 inches. As used herein, and in the claims, a large diameter die is one having a diameter at least twenty times the diameter of the tube to be rolled. Smaller diameter dies are not as effective; the upper limit of the diameters is determined only by the physical limitations of the facilities housing the machine.

The large diameter dies of the invention produce a much higher quality tube with less power requirements than the conventional die rolls heretofore known. This primarily is due to the substantial reduction in skidding or sliding obtained with the new dies, with fewer blemishes resulting on the tube being reduced and less power being dissipated in the form of friction or heat. To illustrate, and with reference to FIG. 8, assume a 3 /2 inch diameter tube is to be reduced to 2 /2 inches by a die roll or die having a stroke length of 26.7 inches. To achieve this length, the 17 inch die roll must move through an arc of approximately 180, in which case the minimum diameter of the die surface moves through a length of only about 22.0 inches. Consequently, the minimum diameter inner surface of the die roll skids relative to the surface of the tube a distance of 4.7 inches or 17.6% of the total arc length. With the 120 inch diameter dies 84 and 102 under the same circumstances, and with the same stroke of 26.7 inches, the dies move through an angle of only about 23 with the arc length of the minimum diameter inner surface of the die being about 26.0 inches. The skidding in this instance of the minimum inner diameter die surface relative to the tube is only 0.7 inch which represents only about 2.7% of the arc length. Further by way of example, with a 2 /2 inch tube or billet to be reduced to 1 /2 inches, a 13 inch diameter die roll is used and is moved through an arc of about 180 to produce a stroke length of 20.4 inches. Under these conditions, the arc length of the minimum diameter die inner surface is 17.3 inches which causes maximum skidding of 3.1 inches. This is 15.2% of the stroke length. With the large diameter die according to the invention under these circumstances, again having a diam eter of 120 inches, with the arc length of 20.4 inches, the minimum arc length is 20.08 inches, representing 0.32 inch of skidding or 1.6% of the stroke length.

An additional advantage is achieved with the large diameter dies embodying the invention. As pointed out above, the large diameter dies need move through an angle of relatively few degrees to achieve a given stroke length and with the link arrangement for the die holders 72 and 106 discussed above, the frame supporting the dies need not be moved at all but can remain stationary throughout the entire strokes of the dies. By eliminating the reciprocating movements of the frame or saddle, the mass which must be reciprocated and the inertia which must be overcome is substantially reduced. This is true even though the sizes of the dies, die holders, and linkages exceeds the sizes of the corresponding die components of the machines heretofore employed.

By using the proper relationships of the angles through which the dies move during their backward and forward strokes, the proper length of the links 54 and 122, and the proper length of the die holders '72 and 106 relative to the connecting roller bearings for the links, the dies can be driven through the stroke cycles and maintained under the proper pressure without any movement of the supporting frame whatsoever. Referring to FIG, 9, the result is achieved by designing the linkages so that the arc of the axis of the lower end of the link 54 formed as the link pivots around the axle 36 is superimposed on part of a prolate trochoidal curve which would be formed by a point corresponding to the same axis of the link during rotation of the die 84. As long as the arcuate path of the axis of the link is substantially superimposed on the prolate trochoidal curve formed by a point corresponding to the same axis, the die 84 will roll along a straight line without any transverse movement of the axis of the axle 36 or the frame 20.

In order to achieve a stroke length of approximately 26 inches with the dies 34 and 102 having diameters of inches, it is necessary that they rotate through an angle of 23. By positioning the axis of the lower end of the link 54 at a point 36 inches from the center of rotation of the die 84, with the distance D1 then being 24 inches, and by making the effective length of the link 54 16% inches long so that the radius R2 is 16% inches, the desired result is acheived, namely that the are formed by the lower link axis will be substantially superimposed on the prolate trochoidal curve through an arc of 11.5 on each side of the vertical. Beyond approximately 11.5", the arc of the lower link axis will deviate above the prolate trochoidal curve and the pressure of the dies 84 and 102 will diminish; consequently, the dies will separate upon continued angular movement of the links. Of course. the various factors involved such as stroke lenghts, link lengths, angles, etc., will vary for each application and, according to the circumstance, it may be desirable to start with other given dimensions rather than stroke length as was done in the above example. The angular and length relationships of the upper die assembly are equally true for the lower die assembly 24.

The above discussion suggests that the arc of the lower axis of the link 54 will be directly superimposed on part of the prolate trochoidal curve formed by the same axis or point during the die stroke. Actually, however, the two curves will not be strictly superimposed and it is not essential that they need be. It is important, though, that the arc and the curve will be superimposed or cross one another at the completion of the forward end of the stroke of the dies since this is where the rear end portions of the dies 84 and 102 meet and determine the final diameter of the tube. The die surface 86 does not taper completely from one end of the die 84 to the other, but the last two or three inches of the die, corresponding to the last two or three degrees of the stroke, are semicylindrical and do not taper. It is at these portions of the stroke and the die where the two curves must be substantially identical insofar as the distance from the axis of the axle 36 is concerned, to assure accurate and true dimensions of the finished reduced tube.

Under the specific conditions discussed, with the radius R2 of the link being 16% inches and with the complete die stroke extending through an arc of 23, the arc and prolate trochoidal curve must intersect at a point located 16% inches from the axis of the axle 36 and Il /2 from a center line through the axle 36, this point being marked P in FIG. 9. The distance from the prolate trochoidal curve to the axis of the axle 36 will be less than the radius R2 for angles between 0 and 11 /2 This is of little consequence, however, since it merely affects the intermediate diameter of the tube being reduced at portions between the original diameter and the final reduced diameter and does not affect the final tube diameter.

By designing the linkages to relieve the die pressure at the end of each stroke, when the distance from the axle axis to the lower link axis is less than the distance from the axle axis to the correspending point of the prolate trochoidal curve, the tube can be fed longitudinally and rotated at the appropriate ends of the strokes. In the example discussed above, the dies can be moved through a 26 arc with pressure relieved as the dies move beyond each feed end of a 23 arc to provide the proper clearanse, about inch in this instance, for axial and rotational movement of the tube. Otherwise, the dies 84 and 102 can be machined so that relief is achieved at the ends of the strokes to the feeding and rotation of the tube, by slightly flaring the ends of the die recesses 86 and 104.

When the dies 84 and 102 move from a position such that they are in contact near their forward or left ends to a position wherein they are in contact near their rearward or right ends, a feed stroke has been accomplished, after which a tube is rotated slightly, through an angle of 40, for example, as previously discussed. The dies then return to the first position with their left ends in contact again to complete an ironing stroke which removes any slight deformities in the tube, due to the meeting points of the dies. At this time, the tube is fed longitudinally, inch for example, and the form stroke is repeated to start another cycle.

FIG. shows a slightly modified tube reducing machine 142. This machine is functionally equivalent to that of FIGS. 24 but employs different supporting linkages for dies 144 and 146. The dies 144 and 146 are connected to pivot members 148 and 150 having arcuate surfaces 152 and 154 bearing on arcuate supporting members 156 and 158. The upper member 156 is backed up by an upper frame member 160 of a machine frame 162 while the lower arcuate member 158 is backed up by a lower frame member 164 with a pre-load set by a wedge 166 corresponding to the wedge 136 of FIG. 4.

The supporting member 156, in combination with the pivot member 148, corresponds ot the link 54 of the machine 12 with the lower axis of the link 54 corresponding to the axis of the member 148. The distance R2 is thus represented by the distance from the center of the supporting member 156 to the axis of the pivot member 148. A prolate trochoidal curve in this instance is established by a point corresponding to the axis of the pivot member 148 located a distance D1 from the central point of contact of the circumference of the die 144 with the lower die 146. The are and the curve again substantially coincide through an arc of 23 to provide the proper stroke. The same relationship holds true for the lower die 146.

The machine 12 of FIGS. 24 is preferred to that of FIG. 10 because the latter involves substantial frictional forces due to the sliding contact between the pivot members 148 and 150 and the supporting members 156 and 158. Also, the manufacturing of the machine 142 is more expensive. However, the principle in each instance is the same and the basic advantages are achieved with both machines.

Because of the relatively small rocking movements of the dies 84 and 182, the drive arrangement therefor can be designed in a manner to produce a better ratio of crank arm movement to die movement. With the same total length of movement of the crank arm, it has been found that the strokes per minute of the dies can be increased from 75 to 124 with substantially no other change being required. On the other hand, a slower crank speed can be used to obtain the same rate of reciprocation.

Referring particularly to FIGS. 4 and 5, the upper die assembly 22 has drive levers 168 and 170 extending from the upper die block 72. The levers 168 and 170 are pivotally connected by connecting pins 172 and 174 to crank arms 176 and 178 on each side of the path of the tube passing through the machine. The crank arms 176 and 178 extend transversely, generally perpendicularly, to the path of the tube rather than parallel thereto, as has been true of the drive arrangements employed with prior tube reducing machines.

With this arrangement, the weight of the components being driven tends to be transmitted less directly to the crank arms and the drive components with the weight more fully supported by the machine frame 20. In addition, the drive arrangement enables a larger ratio of die stroke movement to crank arm movement to be attained. In the machines heretofore known, this ratio was 1:1 whereas with the crank-lever arrangement shown, the ratio can be increased to 1.7: l, by way of example. Hence, for a given speed of the crank arm, the number of strokes attainable for the die can be increased from 75 to 124, for example, or the same rate of reciprocation can be achieved with a much slower crank arm speed.

As shown, the crank arms are driven by a main crankshaft 180 rotatably carried in the base 26 and extending through a wall thereof. The crankshaft 180 includes a pair of outer crank throws 182 and 184 which have crankpins 186 and 188 carrying lower bearing portions 190 and 192 of the crank arms 176 and 178. The crank arms 176 and 178 thereby move the lever arms 168 and to operate the crank arms simultaneously through equal paths. the lower die assembly 24 is driven through a drive lever arm 194 affixed to the lower die block 106 and extending in the same direction as the upper die lever arms. The drive lever arm 194, in this instance, is pivotally connected by a pin 196 to a yoke 198 of a central crank arm 200. The arm 200, in turn, is rotatably connected to a crankpin 202 of a central crank throw 204 of the crankshaft 180, between the crank throws 182 and 184. The crankpin 202 is substantially diametrically opposite the crankpins 186 and 188 with the crank arm 200 thereby moving in a direction generally opposite to the crank arms 176 and 178 to provide a substantially balanced force on the overall drive mechanism and the tube reducing machine than heretofore possible.

The crankshaft has a gear 206 mounted outside the base 26 at one end of the shaft and suitably aflixed thereto. The gear 296, in turn, is driven through a drive gear 208 mounted on a shaft 210 along with a pulley 212. The pulley 212 is driven through a belt 214 and a sheave 216 connected to a heavy-duty drive motor 218. The motor 218 can be of much less horsepower than the motors heretofore used to drive the combination saddles and die rolls of the conventional type.

From the above discussion, it will be seen that the tube reducing machines 20 and 142 according to the invention have many advantages over those heretofore known. The large diameter of the dies 84 and 102 or 144 and 146 produces higher quality tubing because of the greatly reduced skidding action, which also reduces power requirements. The back-up linkage 54 and 122 or 148-158 for the die blocks 72 and 106 or 144 and 146, in combination with the relatively small angular movement required for the dies to produce a given length of stroke, enables the supporting frame to be stationary to reduce power requirements and increase the potential rate of reciprocation of the dies. Further, the relatively small rocking movement of the dies minimizes the chance for the dies to become lose relative to the die holders and break.

The drive arrangement in combination with the small rocking movement enables the dies to be driven through crank arms located transversely to the movement of the tube being reduced to lessen the effect of the weight of the driven members. The specific drive arrangement also enables the cranks to move in opposite directions to minimize stress on the drive shafts and supporting structure.

Various modifications of the above described embodiment of the invention will be apparent to those skilled in the art, and it is to be understood that such modifications can be made without departing from the scope of the invention, if they are within the spirit and the tenor of the accompanying claims.

I claim:

1. A tube reducing machine comprising a stationary frame, a pair of opposed large diameter dies, means for movably connecting the upper die to an upper portion of said frame, means for movably connecting the lower die to a lower portion of said frame, lever means extcnding from each of said dies, crank arms connected to each of said lever arms and extending a common direction transversely of a path of a tube to be moved between said dies, and a crankshaft for driving both of said crank arms.

2. A tube reducing machine comprising a stationary frame, a pair of opposed large diameter dies, means for movably connecting the upper die to an upper portion of said frame, means for movably connecting the lower die to a lower portion of said frame, lever means extending from each of said dies, an arms movable in a direction transversely of a path of a tube to be moved between the dies for operating said lever arms and rocking said dies, said arms being connected to end portions of said lever means and extending in a common direction to one side of the path of the tube, and means located at the side of the path of the tube for driving said arms in opposite directions.

3. In a tube reducing machine, a die holder having a die holder groove including means forming opposed side surfaces and opposed end surfaces, a die in said groove and having an arcuate face with a longitudinally-extending tube-forming surface thereon, a wedge in said groove adjacent a side of said die for urging said die toward one of said side surfaces, an adjustable bolt connected to said wedge and extending to an outer surface of said die holder to enable external adjustment of said bolts and said Wedge, an end wedge adjacent an end of said die between the die end and one of said end walls, a second adjustable bolt connected to said end wedge and extending upwardly through said die holder toan outer surface thereof to enable external adjustment of said end wedge to urge said die toward the opposite end Wall.

4. In a tube reducing machine, a pair of die holders having die holder grooves facing one another with aligned side reference surfaces and end reference surfaces which are aligned when the die holders are in horizontal positions, a die in each of said grooves and having cooperating longitudinally-extending tube-forming surfaces thereon, wedge means adjacent a side of each of said dies for urging said dies toward said reference side surfaces, adjusting means connected to said wedge means to enable adjustment of said wedge means outside said die holder, an end wedge adjacent each of said dies at the end 0pposite said refernce end surfaces, an adjusting bolt connected to each of said end wedges and extending to an outer surface of each of said die holders for external adjustment of said end wedges urging said dies toward said end reference surfaces.

References Cited UNITED STATES PATENTS 1,549,527 8/ 1925 Fielding 72-189 2,153,839 4/1939 Liebergeld 72-189 2,247,863 7/ 1941 Tiedemann 72-215 2,913,936 11/1959 Paetz et a1. 72-189 5 RICHARD J. HERBST, Primary Examiner.

L. A. LARSON, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,357,223 December 12, 1967 Albert P. Tremblay It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 72, for "otuside" read outside column 4, line 2, for "an" read and column 6, line 67, strike out "feed"; lines 67 and 68, for "clearanse read clearance column 7, line 22, for "ot" read to column 8, line 10, for "the" read The and should appear as the beginning of a new paragraph; line 47, for "lose" read loose column 8, line 69, after "extending" insert in column 9, line 3, for "an" read and column 10, line 11, for "refernce" read reference Signed and sealed this 18th day of March 1969.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patent EDWARD M.FLETCHER,JR. Attesting Officer 

1. A TUBE REDUCING MACHINE COMPRISING A STATIONARY FRAME, A PAIR OF OPPOSED LARGE DIAMETER DIES, MEANS FOR MOVABLY CONNECTING THE UPPER DIE TO AN UPPER PORTION OF SAID FRAME, MEANS FOR MOVABLY CONNECTING THE LOWER DIE TO A LOWER PORTION OF SAID FRAME, LEVER MEANS EXTENDING FROM EACH OF SAID DIES, CRANK ARMS CONNECTED TO EACH 